1. Technical Field
The present invention relates to a cooling device, a projector, and a cooling method.
2. Related Art
In recent years, small-sized cooling devices for cooling heat generating devices or the like to prevent equipment provided with such devices from being heated to high temperatures thereby ensuring preferable operations of the equipment have been used or planed to be used in various applications.
For example, there is proposed a projector provided with a solid-state light source having high response to a signal supplied thereto and superior light controllability. Although such a solid-state light source, which is a heat generator, increases in a light emission amount in proportion to a current supply amount, the amount of heat generated also increases similarly. Therefore, if a large amount of current is supplied, the solid state light source is damaged, or the life of the light source is shortened, by the heat the solid state light source generates. Accordingly, it has been proposed to prevent the damage of the solid-state light source and to prolong the life of the solid-state light source by cooling the solid-state light source with the cooling device described above.
Incidentally, such a cooling device is specifically provided with a cooling fluid for cooling the heat source such as the solid-state light source and cooling fluid cooling means for cooling the cooling fluid heated to a high temperature by absorbing the heat generated by the heat source. And, in such a cooling device, in order to achieve quietness and low power consumption of the device, it is preferable that the cooling fluid cooling means is driven corresponding to the heat generation amount of the heat generator.
For example, JP-A-2005-70514 (hereinafter referred to as a first document) and JP-A-2000-35613 (hereinafter referred to as a second document) disclose a technology of disposing a thermometer adjacent to the heat source (light source) and changing the driving state of the cooling fluid cooling means in accordance with the output of the thermometer. According to this technology, since it can be arranged that the cooling fluid cooling means only cools the cooling fluid aggressively when the heat generating amount of the heat source increases, driving the cooling fluid cooling means unnecessarily can be eliminated. Besides the above, there is a related device disclosed in JP-A-11-337897.
However, there is inevitably caused a time lag between cooling of the cooling fluid by the cooling fluid cooling means and absorption of the heat of the heat source by the cooling fluid thus cooled. In particular, the time lag described above becomes large in the cooling device using liquid as the cooling fluid, such as the cooling device for cooling a solid-state light source provided to a projector.
Therefore, according to the technology disclosed in the first and the second documents, the temperature of the heat generator temporarily increases. Accordingly, in the cooling device in the related art, in consideration of the temporary temperature rise of the heat generator, it was necessary to design the device so that the temperature thereof did not reach, for example, the damaging temperature even when the temperature of the heat generator temporarily rose. Therefore, the advantage obtained by cooling the heat source with the cooling device was problematically reduced.